R. Zheng1, H. Lavu1, J. Winter1, E. G. Rosato1, F. Palazzo1, C. J. Yeo1, A. C. Berger1 1Thomas Jefferson University Hospital,Department Of Surgery,Philadelphia, PA, USA
Introduction: An elevated systemic response as measured by circulating levels of identifiable biomarkers is associated with increased post-operative complications and decreased cancer-specific survival. The neutrophil-to-lymphocyte ratio (NLR) is another such novel marker that has been investigated as a prognostic factor in cancer and other diseases. We hypothesized that NLR would be lower in patients undergoing minimally invasive distal pancreatectomy (MIDP).
Methods: Using an IRB approved prospective database, we identified patients who underwent laparoscopic or robotic distal pancreatectomy from 2006-2014. These were matched by age and gender to patients who underwent open distal pancreatectomy during the same time frame. The NLR was calculated from the first postoperative complete blood count with differential. Outcomes measured include complications, blood loss, transfusions, and duration of surgery. Calculations of descriptive statistics, t-tests, and regressions were performed in Stata (v13.0).
Results: Forty-four patients who underwent distal pancreatectomy were included in the study group, with 22 laparoscopic/robotic and 22 open cases during the same study period. The mean age of the open and minimally invasive cohorts was 56.3 years and 56.5 years, respectively. Pathologies of resected specimens included pancreatic neuroendocrine tumor (PNET, n=21, 47.6%), ductal adenocarcinoma (n=13, 29.6%), and Hamoudi tumor (n=4, 9.1%). There were 9 adenocarcinomas in the open group compared to 4 in the MIDP cohort. PNET was more frequent in the MIDP group (16 vs 5). MIDP was associated with a significantly lower postoperative NLR than open surgery (8.4 vs. 19.2, p=0.004). Multivariable linear regression confirms a significant decrease in NLR with the use of laparoscopy when compared to open surgery (p=0.03) independent of age, blood loss, body mass index, or operative duration. Patients who had postoperative complications and received transfusions also had a significantly higher NLR (21.6 vs. 11.5, p=0.04; 26.6 vs. 11.2, p=0.005).
Conclusion: The neutrophil-to-lymphocyte ratio is reliably decreased when performing laparoscopic versus open distal pancreatectomy. An elevated NLR is also significantly associated with higher complication rates. This further validates the use of the NLR as a measure of postoperative inflammation and demonstrates that minimally invasive techniques may minimize the deleterious effects of inflammation. Future studies will examine the impact of NLR on postoperative complications and long term survival after minimally invasive cancer surgery.